The technical field of the invention is controlling motors for propelling motor vehicles, grouping together all motor technologies and more particularly controlling the torque as a function of the rotation speed of electric motors.
An electric motor generally has a high torque at a low rotation speed after which the torque decreases as the rotation speed increases.
In contrast, an internal combustion engine has a maximum torque at intermediate rotation speeds. This maximum torque decreases as soon as a change occurs toward rotation speeds higher or lower than this intermediate rotation speed.
If the driver of an electric vehicle requests a high level of acceleration corresponding to a depression of the accelerator pedal exceeding 50%, they experience a feeling of running out of steam as the speed increases. Because of the torque curve of the electric motor and the single-ratio gearbox, the acceleration of the vehicle drops sharply as the speed of the vehicle increases. This causes a feeling contrary to the experience of most drivers that is proving prejudicial to the adoption of electric vehicles.
In comparison, internal combustion engine vehicles have an acceleration that drops less sharply or even increases as the rotation speed increases in a given gear.
The problem is linked to the shape of the torque and power curves of electric machines compared to those of internal combustion engines. This problem has not been solved because it is at present considered that this forms part of the characteristics of an electric vehicle.